1. Field of the Invention
The present invention relates to a coupler, in which flow channels of a supply side connector and a receiving side connector are communicated in case a valve formed in at least one of the connectors is opened by connecting the connectors. More specifically, the present invention relates to a coupler for connecting a cartridge of a methanol fuel cell with a main body of the fuel cell.
The disclosure of Japanese Patent Application No. 2007-310370 filed on Nov. 30, 2007 including specification, drawings and claims are incorporated herein by reference in its entirety.
2. Discussion of the Related Art
In the prior art, a liquid-consuming device is refilled with a consumable liquid such as fuel by connecting a cartridge containing the liquid with a container of the device, or by replacing the container of the device itself with a spare container containing the liquid.
In recent years, fuel cells have been used as a power source of portable electronic devices such as a laptop computer, a mobile phone etc. for the purpose of extending usable period of the devices without charging. The fuel cell is capable of generating electricity by supplying fuel and air thereto. That is, the fuel cell is capable of generating over a long period of time by merely supplying the fuel thereto. Thus, the fuel cell is a promising energy source for the portable electronic devices and therefore required to be downsized.
For instance, a direct methanol fuel cell (to be abbreviated as DMFC hereinafter) using methanol fuel of high energy density can be downsized comparatively easily, and the methanol fuel can be handled comparatively easily. Therefore, the DMFC is expected to be used as a power source of the electronic devices. There are two kinds of liquid fuel supplying systems of the DMFC such as an “active” system and a “passive” system are known in the art. Specifically, according to the active system, the liquid fuel is fed to the fuel cell by an external power. Meanwhile, according to the passive system, the liquid fuel is aspirated to the fuel cell in a passive manner by a capillary action or the like.
For example, according to Japanese Patent Laid-Open No. 2007-57007 and Japanese Patent Laid-Open No. 2007-194054, a satellite type (i.e., external injection type) fuel cartridge is used to supply liquid fuel to a fuel tank. Specifically, according to the teachings of Japanese Patent Laid-Opens Nos. 2007-57007 and 2007-194054, the liquid fuel is supplied and interrupted to the fuel tank using a coupler constituted of a nozzle and a socket each having a valve mechanism inside. In addition, Japanese Patent Laid-Open No. 2003-172487 discloses a connecting device having a plug and a socket to be engaged with the plug. According to the teachings of Japanese Patent Laid-Open No. 2003-172487, flow channels formed individually in the plug and the socket are communicated by inserting the plug into the socket thereby opening the valve.
According to the teachings of the Japanese Patent Laid-Opens Nos. 2007-57007 and 2007-194054, the socket and the plug are provided individually with a valve element. Specifically, the valve element is adapted to be pushed onto a valve seat by a spring situated behind in its axial direction, and the valve element comprises a protruding portion such as an operating portion protruding from a portion to be contacted with the valve seat. Therefore, in case the plug is inserted into the socket, the protruding portions of each valve element push each other and moved backwardly away from the valve seat against the elastic forces of the springs. As a result, the valve is opened. To the contrary, in case of withdrawing the plug from the socket, each of the valve elements is pushed toward the valve seat thereof by the spring as a reduction of a depth of the plug insertion, and contacted gradually with the valve seat to open the valve. At the same time, the protruding portions of the valve elements are detached from each other, and the plug is disengaged from the socket.
According to the teachings of the Japanese Patent Laid-Opens Nos. 2007-57007 and 2007-194054, the valve elements are thus adapted to push each other at the protruding portions. Therefore, in case the plug is inserted into the socket, a distance between the valve seats is rather long, and a large amount of the liquid may remain between the valve seats under the condition in which the valves of both plug and the socket are opened. For this reason, when the plug is withdrawn from the socket, the remaining liquid may leak therefrom. Thus, the liquid may be wasted and it is not easy to cope with the leaked liquid. In addition, the liquid of high responsiveness such as methanol, formic acid and so on are used as the fuel of the fuel cell. For example, methanol of more than 99.8% concentration is designated as a poisonous and deleterious substance because it is harmful to the humans.
In addition, according to the teachings of the Japanese Patent Laid-Opens Nos. 2007-57007 and 2007-194054, an order of the valve elements to be opened is governed by a relation between strengths of elastic forces of the springs pushing the valve elements of the socket and the plug. Specifically, an elastic force of the spring pushing the valve element of the liquid container side is relatively weakened to open the valve element earlier in case of inserting the plug into the socket, and to close the valve element later in case of withdrawing the plug from the socket. Therefore, in case of regulating the elastic force of one of the springs of the socket and the plug, the elastic force of other spring is also need to be adjusted in order not to change such difference or ratio between the elastic forces of the springs. Thus, according to the devices taught by the Japanese Patent Laid-Opens Nos. 2007-57007 and 2007-194054, an adjustment of the elastic force of the springs is rather complicated, and the freedom of choice is thereby restricted.
On the other hand, according to the connecting device taught by Japanese Patent Laid-Open No. 2003-172487, a valve element of a plug is pushed by an immobile portion (or a structural portion) of a socket, and a valve element of the socket is pushed by an immobile portion (or a structural portion) of the plug. In addition, the valve elements of both socket and the plug are not especially provided with a protruding portion, therefore, a distance between valve seats is short. However, according to the teachings of Japanese Patent Laid-Open No. 2003-172487, leading end portions of the valve elements are protruded from leading ends of the socket and the plug. Especially, a packing member of the valve element of the socket side is protruded to the leading end side of the socket to be pushed by the plug. Therefore, the packing member may be damaged and deteriorated easily, and a durability of the packing member is thereby degraded. In addition, since the leading end portion of the valve element of the socket or the plug is exposed, the valve element may be pushed accidentally by a projection therearound when a container or the like being connected with the plug and the socket is laid carelessly. For the same reason, the valve thus structured may be opened easily even for children by pushing the valve element.